The present invention relates to switch circuits which shut off an engine, and more particularly to circuits for shutting off engines when a low oil condition exists.
Various types of circuits are known for shutting off an engine when a particular condition exists, such as low oil or low oil pressure in the crankcase, or when a sufficient pressure is not present on the seat of a riding vehicle. Some of these prior art switch circuits are connected to indicator systems that provide an audible or visual signal when, for example, the oil pressure is too low.
One known low oil switch has one terminal connected to a float which floats near the surface of the oil in the crankcase. The other terminal is typically affixed to the bottom of the crankcase and is connected to ground. When the oil level drops below a predetermined level, the floating terminal contacts the terminal at the bottom of the crankcase, shorting ignition pulses to ground and shutting off the engine.
A major problem with this prior art device is that the float switch arrangement is very expensive, increasing the cost of the engine.
Therefore, it is desirable to design an engine shut-off circuit that is both simple and inexpensive.